Process of burning-off oil on the surface of water basins

ABSTRACT

Method and means are presented for destroying drifting oil layers on the surface of water basins by sustained combustion in a zone contiguous to the oil layer and in relative motion with respect thereto. In the method for thus combating drifting oil, a plurality of jets of combustion sustaining gas, in particular compressed air, are blown against the oil layer in said zone for sustaining combustion therein. In the combating means a hollow element is connected to a source of pressure gas, in particular compressed air, and kept afloat at the surface of the water with longitudinally spaced discharge openings on the element blowing the pressure gas against the oil layer in said zone for sustaining combustion therein.

United States Patent PROCESS OF BURNING-OFF 01L ON THE SURFACE OF WATER BASINS 7 Claims, 9 Drawing Figs.

U.S. Cl 431/8, 210/63 Int. Cl F23c 5/00 Field oiSearch 61/1; 210/63, 242, 523, D16. 21; 431/2, 4, 7, 8, 170, 298, 326

[56] References Cited UNITED STATES PATENTS 1,832,280 11/1931 Coultas 431/4 3,491,023 1/1970 McCormick 210/242 X Primary Examiner-Samih N. Zahama Attorney-Eric Y. Munson ABSTRACT: Method and means are presented for destroying drifting oil layers on the surface of water basins by sustained combustion in a zone contiguous to the oil layer and in relative motion with respect thereto. 1n the method for thus combating drifting oil, a plurality of jets of combustion sustaining gas, in particular compressed air, are blown against the oil layer in said zone for sustaining combustion therein. In the combating means a hollow element is connected to a source of pressure gas, in particular compressed air, and kept afloat at the surface of the water with longitudinally spaced discharge openings on the element blowing the pressure gas against the oil layer in said zone for sustaining combustion therein.

PATENTED JUH22 Ian SHEET 1 OF 4 I J j PATENTEU JUN22|971 3586.469

SHEET 3 OF 4 PROCESS OF BURNING-OFF OIL ON THE SURFACE OF WATER BASINS This invention relates to method and means for combating oil drifting about on the surface of water basins. Spilled layers of crude oil and the fractions thereof adrift on the surface of water constitute a pollution danger for surrounding shores and may cause great damage in nature. Among earlier methods for combating spill oil there were made trials to set fire to such oil layers in order to destruct them out at sea. Thus, floating crude oil spilled out at a recent tanker catastrophe was ignited by an inflammatory agent such as napalm but with rather small a success, since continuous steady burning could only be maintained for short periods of time, probably as a result of the cooling influence of water on the oil layer.

It is an object of this invention to realize a locally confined continuously sustained buming-off of floating oil so that drifting layers of spill oil can be destroyed while still on open water and before reaching surrounding shores. Another object of the invention is to direct against the oil layer, in a restricted zone contiguous thereto, a plurality of jets of combustion sustaining gas under pressure, in particular compressed air, so that the interrnixing of oil and gas in said zone will be adequate enough to ensure continuous vehement burning of the oil therein.

For the above and other purposes there is according to the invention provided a method for combating oil drifting about as a layer on the surface of water basins comprising the steps of blowing a plurality of jets of combustion sustaining gas under pressure against said oil layer in a restricted zone contiguous thereto, igniting said zone for creating combustion of oil therein, and displacing said zone relative to said oil layer or vice versa for feeding new oil to said zone to be destroyed by burning therein. The apparatus for carrying out the invention comprises means for combating oil drifting about as a layer on the surface of water basins comprising a source of pressure gas capable of sustaining combustion, a hollow element, a plurality of discharge openings on said element spaced along the length thereof, means for keeping said element afloat at the surface of the water with said discharge openings thereof substantially level with said oil layer and directed thereagainst in a zone contiguous thereto, and a connection between said source and said element for supplying pressure gas to said element and blowing it through said discharge openings against said oil layer in said zone for purposes of sustaining combustion therein upon ignition of said zone and movement of said oil layer relative thereto or vice versa.

The above and other objects of the invention will become obvious from the following description and from the accompanying drawings in which four preferred embodiments of the invention are illustrated by way of example. It should be understood that these embodiments are only illustrative of the invention and that various further modifications thereof may be made within the scope of the claims.

In the drawings FIG. 1 shows a top view of a body of water supporting means thereon for combating drifting oil according to one embodiment of the invention. FIG. 2 shows a vertical section of the body of water and rear end view of the means in FIG. 1. FIG. 3 is a vertical section on an enlarged scale seen on the line 3-3 in FIG. 1. FIG. 4 is a fragmentary view seen on the line 4-4 in FIG. 3. FIG. Sis a section on the line 5-5 in FIG. 1. FIG. 6 is a top view of a body of water supporting a modified embodiment of the invention. FIG. 7 is a top view of a shore and adjoining body of water supporting a further embodiment of the invention. FIG. 8 is a vertical section of the body of water and a rear end view of the means in FIG. 7. FIG. 9, finally, is a fragmentary perspective and sectional view of a still further embodiment of the invention.

In the embodiment illustrated in FIGS. 15 an oil patch 11 of crude oil or some fraction thereof is adrift on a water surface 10. A metallic framework 12, for example of T-shape is immersed under the water surface and is kept afloat by floats l3 pivoted to the framework 12. The framework 12 is towed by a pair of vessels 14 which by means of wires 15 are made fast to towing posts 16 on the framework 12. The wires 15 are extended through a number of aligned conventional floating booms 17 which provide continuous oil fence means for bordering-in and guiding the oil layer 11 towards the framework 12. As depicted in FIG. 5, the booms 17 include a float body 18 penetrated by the wire 15, depending flaps 19 carried by each float body 18 and sealingly interconnected from boom to boom, and hanging weights 20 attached to the depending ends of the flaps l9.

A hollow element 23 includes a number of laterally spaced but interconnected flexible tubes 24 of plastic material. The tubes 24 are provided with rows of a multitude of discharge openings 22 spaced along the length of the tubes 24 and with a diameter preferably smaller than 0.5 millimeters. By means of attached suitably chosen weights 25 the hollow element 23 is kept immersed in the water afloat at the surface thereof and above the framework 12 with the discharge openings 22 slightly above surface and substantially level with the oil layer 11. The tubes 24 are afi'ixed to the framework 12 vertically movably as by means of wires 21 for permitting the tubes 24, while afloat at the water surface, on the one hand to be towed together with the framework 12 and on the other to freely follow the wave heaving above the framework 12 for substantially reducing overwashing and exposure. The element 23 represented by the tubes 24 is connected by means of hoses 26 to one or plural sources of combustion sustaining pressure gas, preferably air compressors 27 standing on the vessels 14. The hoses 26 are carried by the booms 17.

From the compressors 27 air under pressure is supplied to the element 23 for sustaining, by the oxygen contained therein, the combustion in the zone above the tubes 24 when the oil layer 11 reaches the latter and is washed thereover either by drifting with wind and water currents towards the element 23 or when the element 23 is towed by the vessels 14 towards the layer. In the zone above the tubes 24 the oil layer 11 is subjected to a plurality of fine gas jets from the discharge openings 22 hitting the layer transversely from below and vehemently mixing the oil with gas and conditioning the zone for continuous sustained combustion. The oil zone above the tubes 24, thus effectively blown through and oxygenizcd, is ignited for example by means of torches or matches. Preferably there are arranged ignition coils 28 on the tubes 24 which coils 28 are fed by an electric heating current via a cable 29 from a current source 30 on one of the vessels 14. If an increase of the intensity of combustion is desired, a fuel gas container 31 may be provided on one of the vessels 14. The container 31 supplies fuel gas such as coal gas via a conduit 32 to fuel nozzles 33 arranged at the tubes 24 adjacent to the ignition coils 28. The element 23 is displaced relative to the layer 11 preferably at such rate that the layer 11 flowing-on thereagainst will have time to burn away continuously and substantially completely in the zone above the tubes 24. During towing of the element 23 one or both vessels 14 can, in order to avoid possible fire hazards, choose a course outside of the oil layer 11 by adjusting the length of the wires 15 accordingly. For increasing the fire resistance the plastic tubes 24 may be made with an asbestos reinforcement, although sufficient fire protection normally is offered by the water surrounding the tubes 24.

In the embodiment illustrated in FIG. 6 there is used an element 23 with tubes 24 carried afloat above a framework 12 in full analogy with the embodiment shown in FIGS. 1--5. However, for towing of the framework 12 there is in this case made use of only one vessel 14 safely far ahead of theoil burning zone. Furthermore, the tubes 24 are covered by an asbestos fabric 35 capable of being blown through by the gas jets and affixed forwardly on the framework for keeping the plastic material tubes 24 protected against possible overheating. Behind the element 23 there is formed an elevated water threshold or ban-ier 36 by providing a surface oil fence means. Thus, a perforated tube 37 is by means of spars 38 connected to the framework 12 and, as depicted by broken lines in FIGS. 3 and 6, kept on a depth of a few meters with respect to the framework 12 and connected by a hose to the hose 26 and the compressor 27. Via the perforations of the tube 37 a curtain of air bubbles is led up to the surface raising above the tube 37 a locally confined elevated barrier of water 36 on the surface in a manner well known in the art. The barrier 36 is used as a surface oil fence means for bordering-in and keeping the oil layer 11 in the combustion zone above the element 23.

In the embodiment illustrated in FIGS. 7, 8 lines of interconnected oil booms 17 are moored by means of weights +30 to the bottom of the sea near the shore 413. An oil patch drifting with wind or currents is caught by the oil booms i7 and guided towards an element 23 laid out between the lines of booms 1'7 and provided with discharge openings spaced along the length of the element 23. More particularly, the element 23 consists of a single floating tube 24 of plastic material provided with an asbestos covering, now shown, and arranged similarly to the tubes 24 in the embodiment illustrated in FIGS. ll-5. By means of weights dll there is furthermore immersed and moored at the bottom of the sea a perforated tube 37 for forming, when supplied with compressed air, an air bubble curtain and thereby an above-surface water barrier 36 above the tube 37 which barrier 36 guides the oil layer it towards the combustion zone at the element 23. For purposes of increasing the combustion intensity gaseous oxygen additive may be led over to the compressed air hose as from an oxygen tank 39 for liquid oxygen placed ashore, whereby the oxygen content in the compressed air may be increased. In case of need fuel agents such as gasoline, spirit, coal gas and the like may be supplied to the combustion zone via special supply conduits, now shown, or as a dosage to the compressed air in the hose 26 in case the combustion tends to become sluggish when en countering large accumulations of heavy oil in the combustion zone.

In the embodiment illustrated diagrammatically in FIG. 9 the oil layer it reaches a floating continuous barrier consisting of a long tube as arranged floatingly slightly above the water surface it) and provided with narrow discharge slits d directed along the water surface with a slight downward inclination thereagainst towards an advancing oil layer 11 thereon. The tube as is carried by a series of interconnected towed or moored conventional floating booms i7 barring the way of the oil layer. By the tube 46 combustion sustaining pressure gas jets are blasted through the slits d5 hitting the oil layer level with the water line and skimming or whirling up the oil and mixing it with gas so as to form an intensively burning combustion zone adjacent and in front of the tube 46. For purposes of ignition there may as before be used torches or other means, not shown, such as ignition coils with or without fuel gas noules as illustrated in FIG. 4.

What we claim is:

1. A method for combating oil drifting about as a layer on the surface of water basins comprising the steps of blowing a plurality of jets of combustion sustaining gas under pressure against said oil layer in a restricted zone contiguous thereto, igniting said zone for creating combustion of oil therein, and displacing said zone relative to said oil layer or vice versa for feeding new oil to said zone to be destroyed by burning therein.

2. A method according to claim 1 comprising the further step of displacing said zone relative to said oil layer or vice versa at a rate at which said oil layer is destroyed by burning in said zone.

3. A method according to claim 1 comprising the further step of keeping said gas jets adjacent to the surface of the water and directing them upward into said oil layer.

d. A method according to claim 1 comprising the further step of keeping said gas jets adjacent to the surface of the water and directing them therealong against said oil layer.

5. A method according to claim 1 comprising the further steps of bordering-in and guiding said oil layer towards said zone by surface oil fence means.

6. A method according to claim 1 comprising the further steps of keepin a hollow element afloat on the water, supplymg compresse air to said hollow element, and forming said gas jets by blowing compressed air from said element through a plurality of longitudinally spaced discharge openings thereon out against said oil layer.

7. A method according to claim 1 comprising the further steps of forming said jets by compressed air and increasing the intensity of combustion in said zone by increasing the content of oxygen in the compressed air or by the dosage of fuel thereto or directly to the zone. 

2. A method according to claim 1 comprising the further step of displacing said zone relative to said oil layer or vice versa at a rate at which said oil layer is destroyed by burning in said zone.
 3. A method according to claim 1 comprising the further step of keeping said gas jets adjacent to the surface of the water and directing them upward into said oil layer.
 4. A method according to claim 1 comprising the further step of keeping said gas jets adjacent to the surface of the water and directing them therealong against said oil layer.
 5. A method according to claim 1 comprising the further steps of bordering-in and guiding said oil layer towards said zone by surface oil fence means.
 6. A method according to claim 1 comprising the further steps of keeping a hollow element afloat on the water, supplying compressed air to said hollow element, and forming said gas jets by blowing compressed air from said element through a plurality of longitudinally spaced discharge openings thereon out against said oil layer.
 7. A method according to claim 1 comprising the further steps of forming said jets by compressed air and increasing the intensity of combustion in said zone by increasing the content of oxygen in the compressed air or by the dosage of fuel thereto or directly to the zone. 